Iron Boy Scotch is one of those in charged of protecting one of the territories of Kaidou. When X Drake came to his island, Scotch told him that it was one of Kaidou's favorite places and that it wouldn't do any good to upset him. However, instead of scaring him, it had the opposite reaction.

One of the Yonkou that control the New World. Not much so far is known about Kaidou, unless he defeated Gekko Moriah killing all his crew and that he intended to take advantage of the Marineford war for finishing Shirohige, but he was aparently intercepted by Shanks.